Mr Castro, aged 44 and long seen as a rising star in the party, served as housing secretary under President Barack Obama and was on the list of Hillary Clinton’s potential running mates for the 2016 election.

Having a Mexican grandmother, he has used his background to criticise Mr Trump’s policies on border security.

But correspondents say he does not have widespread name recognition and may struggle to make an impression in a crowded field.

He made his announcement in his home town of San Antonio, Texas, where he was mayor from 2009 to 2014.

His launch comes a day after news emerged that Hawaii Congresswoman Ms Gabbard would also announce a bid.

In an interview due to air on CNN on Saturday evening, she says: “There are a lot of challenges that are facing the American people that I’m concerned about and that I want to help solve.”

A native of American Samoa and an Iraq veteran, Ms Gabbard, 37, is seen as an outspoken figure on the left of the party.

Related Articles

[ad_1] Image copyright PA Image caption Saudi writer Jamal Khashoggi was a columnist for the Washington Post Turkey has given its first official statement on how it believes writer Jamal Khashoggi was killed, saying he was immediately strangled. The statement follows weeks of media reports about the murder at the Saudi consulate in Istanbul on […]

[ad_1] Image copyright AFP Image caption The $3bn Chinese-funded railway is Kenya’s biggest infrastructure project since its independence Three Chinese nationals have been charged with attempting to bribe investigators working on an alleged ticketing scam in a massive Kenyan railway project. Some $10,000 (£8,000) a day was being stolen in the scheme, local media say. […]

[ad_1] In July 2018 a horrifying video began to circulate on social media. It shows two women and two young children being led away at gunpoint by a group of Cameroonian soldiers. The captives are blindfolded, forced to the ground, and shot 22 times. The government of Cameroon initially dismissed the video as “fake news.” […]